To determine the structural and functional roles of lipids and the mechanisms of biosynthesis of lipids in trypanosomatid flagellates by: 1) a complete analysis of the lipids of intact flagellates, 2) observation of the ability of intact flagellates to incorporate and to modify isotopically-labeled lipids, 3) isolation of flagellate organelles (kinetoplast-mitrochondrion, flagellum, etc.) and characterization of their lipids, 4) observation of the distribution of isotopically-labeled lipids among these organelles.